At least 19 school children and two adults are dead after a bus crash in South Africa, according to the school officials.

The Gauteng Province's education department tweeted "18 learners" and two adults , including the driver, were killed on the scene after the bus collided head-on with a truck. The department said "this is a huge loss & we're deeply pained by the tragic news."

The crash occurred as the students were travelling home from Mahlenga High. ER24 medical service says responders found about 13 children trapped inside the vehicle after its flames were put out. The other children were found outside the minibus.

Seven students were rescued by emergency services.

The emergency service says the cause of the crash is not yet known. It occurred between the communities of Verena and Bronkhorstspruit.